U.S. patent number 6,039,903 [Application Number 09/216,682] was granted by the patent office on 2000-03-21 for process of making a bicomponent fiber.
This patent grant is currently assigned to BASF Corporation. Invention is credited to Matthew B. Hoyt, Otto M. Ilg, Diane R. Kent, Morris K. Queen.
United States Patent |
6,039,903 |
Kent , et al. |
March 21, 2000 |
Process of making a bicomponent fiber
Abstract
Novel bicomponent fibers have a polyamide domain and a
contaminant-containing polymer domain which is embedded entirely
within, and thereby completely surrounded by, the polyamide domain.
The preferred bicomponent fibers have a sheath-core structure
wherein the polyamide domain constitutes the sheath and the
contaminant-containing polymer constitutes the core. Surprisingly,
even though the core is formed of a contaminant-containing polymer
(which is difficultly spinnable), the bicomponent fibers are
readily spinnable and exhibit properties which are comparable in
many respects to fibers formed from 100% polyamide. Preferably, the
fibers are concentric sheath-core bicomponent fibers having an
uncontaminated nylon-6 sheath and a core formed from nylon-6 having
a relatively high level of contamination in the form of the cyclic
dimer of caprolactam and/or nylon-6 derived from colored
regenerated post-consumer nylon carpet fibers.
Inventors: |
Kent; Diane R. (Arden, NC),
Hoyt; Matthew B. (Arden, NC), Ilg; Otto M. (Asheville,
NC), Queen; Morris K. (Clyde, NC) |
Assignee: |
BASF Corporation (Mt. Olive,
NJ)
|
Family
ID: |
21878333 |
Appl.
No.: |
09/216,682 |
Filed: |
December 18, 1998 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
998830 |
Dec 29, 1997 |
5885705 |
|
|
|
Current U.S.
Class: |
264/40.1;
264/172.12; 264/172.15; 264/172.18; 264/210.8; 264/78 |
Current CPC
Class: |
D01D
5/253 (20130101); D01F 8/12 (20130101); Y10T
428/2929 (20150115); Y10T 428/2924 (20150115); Y10T
428/2931 (20150115) |
Current International
Class: |
D01F
8/12 (20060101); D01D 5/253 (20060101); D01D
5/00 (20060101); D01D 005/12 (); D01D 005/34 ();
D01F 008/06 (); D01F 008/12 () |
Field of
Search: |
;264/40.1,78,172.12,172.15,172.18,177.13,210.8 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Tentoni; Leo B.
Attorney, Agent or Firm: Nammo; Laura D.
Parent Case Text
This application is a divisional of application Ser. No.
08/998,830, filed Dec. 29, 1997, now U.S. Pat. No. 5,885,705.
Claims
What is claimed is:
1. A method of making a bicomponent fiber comprising directing
respective melt flows of a polyamide and a contaminant-containing
polymer to a spinneret, forming a bicomponent fiber by extruding
the melt flows of the polyamide and the contaminant-containing
polymer through orifices of the spinneret such that the
contaminant-containing polymer is present as one domain of the
fiber cross-section and the polyamide is present as another domain
in the fiber cross-section, and thereafter quenching the
bicomponent fiber, wherein the contaminant-containing polymer is
polyamide and the contaminant in the contaminant-containing polymer
is the cyclic dimer of caprolactam.
2. A method as in claim 1, wherein the contaminant-containing
domain includes regenerated polymer.
3. A method as in claim 1, which further comprises the step of
drawing the bicomponent fiber at least 10%.
4. A method as in claim 2, wherein the regenerated polymer is
colored.
5. A method as in claim 2, wherein the core domain is nylon derived
from post-consumer carpet fibers.
6. A method of making a concentric sheath-core bicomponent fiber
comprising directing respective melt flows of an uncontaminated
polyamide and a contaminant-containing polyamide to a spinneret,
forming the bicomponent fiber by extruding the respective melt
flows through orifices of the spinneret such that the
contaminant-containing polyamide is present as the core of the
fiber and the uncontaminated polyamide is present as the sheath of
the fiber, and thereafter quenching the bicomponent fiber, wherein
the contaminant in the core is the cyclic dimer of caprolactam.
7. A method as in claim 6, wherein the sheath comprises about 50%
by weight or less of the fiber, and the core comprises about 50% by
weight or greater of the fiber.
8. A method as in claim 7, wherein the sheath comprises about 20%
by weight of the fiber, and the core comprises about 80% by weight
of the fiber.
9. A method of making a concentric sheath-core bicomponent fiber
comprising directing respective melt flows of a polyamide polymer
and a regenerated, colored polyamide polymer to a spinneret,
forming the bicomponent fiber by extruding the respective melt
flows of the polyamide polymer and the regenerated, colored
polyamide polymer through orifices of the spinneret such that the
polyamide polymer is present as the sheath of the fiber and the
regenerated, colored polyamide polymer is present as the core of
the fiber, and thereafter quenching the bicomponent fiber.
10. A method as in claim 9, which further comprises the step of
drawing the bicomponent fiber at least 10%.
11. A method as in claim 9, wherein the regenerated polymer is
recycled carpet comprised of about 90% nylon-6 and about 10% of
non-polymeric contaminants.
12. A method as in claim 11, wherein the polyamide polymer is
nylon-6.
13. A method as in claim 12, wherein the fiber is trilobal.
14. A method of making a colored bicomponent fiber comprising
comparing a regenerated, colored polymer to a color standard,
adding a color leveler to said regenerated colored polymer in an
amount sufficient to obtain a regenerated, colored polymer having a
color which matches said color standard, and melt-spinning a
fiber-forming polymer and the regenerated, colored polymer into a
colored bicomponent fiber such that the regenerated, colored
polymer is present as a core domain that is completely surrounded
by a sheath domain of the fiber-forming polymer.
15. The method of claim 14, wherein said color leveler is carbon
black.
16. The method of claim 14 or 15, wherein the sheath is formed of
nylon 6 and the core is formed of a regenerated polymer which is
recycled carpet comprised of about 90% nylon-6 and about 10% of
non-polymeric contaminants.
17. A method as in claim 1, wherein the contaminant in the
contaminant-containing polymer domain is present in an amount that
is at least about three times greater than any residual contaminant
that may be present in the polyamide domain.
18. A method as in claim 6, wherein the contaminant in
contaminant-containing polyamide core is present in an amount that
is at least about three times greater than any residual contaminant
that may be present in the polyamide sheath.
Description
CROSS-REFERENCE TO RELATED APPLICATION
This application is related to, and claims domestic priority
benefits from, U.S. Provisional patent application Ser. No.
60/034,745 filed on Jan. 10, 1997, the entire content of which is
expressly incorporated hereinto by reference.
FIELD OF INVENTION
The present invention relates generally to the field of synthetic
fibers. More particularly, the present invention relates to
synthetic bicomponent fibers having a sheath-core structure. In
particularly preferred forms, the present invention is embodied in
multi-lobal bicomponent fibers having a polyamide sheath entirely
surrounding a core formed of a contaminant-containing polymeric
material.
BACKGROUND AND SUMMARY OF THE INVENTION
Polyamide has been utilized extensively as a synthetic fiber. While
its structural and mechanical properties make it attractive for use
in such capacities as carpeting, it is nonetheless relatively
expensive. It would therefore be desirable to replace a portion of
polyamide fibers with a core formed from a relatively lower cost
material.
In this regard, some polymeric materials that are attractive
candidates as a partial replacement of the polyamide are
"off-specification"--that is, contain a contaminant. For example,
"off-specification" nylon-6 having relatively high levels of the
cyclic dimer of caprolactam is particularly troublesome when
attempted to be melt-spun. Such "off-specification" nylon 6 can be
obtained from a number of sources due, for example, to its being
manufactured with methods that produce high levels of the cyclic
dimer contaminant, or have avoided (or minimally exposed) to a
dimer extraction step. However, replacing a portion of a 100%
polyamide fiber with a core portion of a contaminant material may
affect the mechanical properties of the fiber to an extent that it
would no longer be useful in its intended end-use application
(e.g., as a carpet fiber).
Furthermore, many regenerated polymeric materials are already
colored (e.g., by use of a colorant or dye). Therefore, their use
as a material to make useful products (e.g., carpet fibers) is
usually limited by the color of the regenerated polymeric materials
that may be obtained. Typically, only clear regenerated polymeric
materials are employed for such purposes since the manufacturer can
then add pigments or dyes to provide products of desired color.
Recently, U.S. Pat. No. 5,549,957 has proposed multi-lobal
composite fibers having a nylon sheath and a core of a
fiber-forming polymer which can be, for example, "off spec" or
reclaimed polymers. (Column 4, lines 6-8.) The core can be
polypropylene, polyethylene terephthalate, high density
polyethylene, polyester or polyvinyl chloride. (Column 4, lines
17-20.) The core is covered with a sheath of virgin nylon which
constitutes between 30% to 50% by weight of the core/sheath fiber.
(Column 3, lines 65-67.)
The presently known prior art therefore evidences the fact that
contaminant-containing polymeric materials--particularly, nylon-6
having a relatively high level of the cyclic dimer of
caprolactam--have not been employed as a structural component of
finished bicomponent synthetic fiber structures.
Broadly, the present invention relates to a bicomponent fiber
structure having a polyamide domain and another distinct
cross-sectional domain formed of polymeric material having a
relatively high level of contaminant. The contaminant-containing
polymeric domain is embedded entirely within, and thus completely
surrounded by, the polyamide domain. Preferably, the fibers of this
invention have a concentric sheath-core structure whereby the
polyamide domain forms the sheath and the contaminant polymer forms
the core. Surprisingly, even though the core is formed of a polymer
having relatively high levels of contaminant, the bicomponent
sheath-core fibers of this invention exhibit properties which are
comparable in many respects to fibers formed from 100% (virgin)
polyamide.
In another aspect, the present invention relates to a bicomponent
fiber structure having a polyamide domain and another distinct
cross-sectional domain formed of a regenerated colored polymeric
material. The regenerated polymeric domain is embedded entirely
within, and thus completely surrounded by, the polyamide domain.
Preferably, the fibers of this invention have a concentric
sheath-core structure whereby the polyamide domain forms the sheath
and the regenerated polymer forms the core. Surprisingly, even
though the core is formed of a regenerated colored polymeric
material, the bicomponent sheath-core fibers of this invention
exhibit properties which are comparable in many respects to fibers
formed from 100% (virgin) polyamide. For example, the virgin
polymer sheath component of the bicomponent fibers of this
invention can be colored to an extent that the colored regenerated
polymeric core material in the core is "hidden".
A further aspect of this invention is that the colored regenerated
polymeric material be blended with a color-leveler--for example, a
black pigment, such a carbon black. In this regard, it is known
that most regenerated (recycled) polymeric materials will have some
color variation, typically a shade of gray-green. According to the
present invention, therefore, the regenerated colored polymeric
material would first be measured against a known color standard. A
specified amount of a color leveler (e.g., carbon black) would then
be added to the regenerated colored polymeric material to correct
its color to the known standard. Thereafter, the color-corrected
regenerated polymeric material may be incorporated into the core of
a sheath-core fiber according to this invention.
These, as well as other aspects and advantages of this invention,
will become more apparent after careful consideration is given to
the following detailed description of the preferred exemplary
embodiments thereof.
DETAILED DESCRIPTION OF THE PREFERRED EXEMPLARY EMBODIMENTS
As used herein and in the accompanying claims, the term
"fiber-forming" is meant to refer to at least partly oriented,
partly crystalline, linear polymers which are capable of being
formed into a fiber structure having a length at least 100 times
its width and capable of being drawn without breakage at least
about 10%. The term "non-fiber-forming" is therefore meant to refer
to polymers which may be formed into a fiber structure, but which
are incapable of being drawn without breakage at least about
10%.
The term "fiber" includes fibers of extreme or indefinite length
(filaments) and fibers of short length (staple). The term "yarn"
refers to a continuous strand or bundle of fibers.
The term "bicomponent fiber" is a fiber having at least two
distinct cross-sectional domains respectively formed of different
polymers. The term "bicomponent fiber" is thus intended to include
concentric and eccentric sheath-core fiber structures and
island-in-sea fiber structures. Preferred according to the present
invention are concentric bicomponent sheath-core fiber structures
having a polyamide sheath and a contaminant-containing polymer
core, and thus the disclosure which follows will be directed to
such a preferred embodiment. However, the present invention is
equally applicable to other bicomponent fiber structures having a
polyamide domain and a non-fiber-forming contaminant-containing
polymer domain embedded entirely within, and thus completely
surrounded by, the polyamide domain.
The term "linear polymer" is meant to encompass polymers having a
straight chain structure wherein less than about 10% of the
structural units have side chains and/or branches.
The terms "contaminated" and "uncontaminated" refer to a difference
in the presence of an undesirable contaminant component wherein the
"uncontaminated" material has less than 80% of the component
present than the "contaminated" material. Furthermore, the
"uncontaminated" material when spun as a single component fiber
forming resin exhibits 50% less spinning interruptions than the
"contaminated material" when spun into a similar fiber. In this
regard, a spinning interruption is an event in the extrusion of
fiber of filaments wherein the continuous production of fiber or
filaments is interrupted. One major cause is threadline instability
due to deposits on the spinneret face. Such events reduce the
capacity of spinning equipment, produce waste, and often result in
less than full yarn packages.
The term "regenerated polymer" is meant to refer to recycled
post-consumer polymeric waste materials which are, in and of
themselves, non-fiber-forming. Thus, a "regenerated polymer" in
accordance with the present invention is encompassed within the
definition of a contaminant component.
The preferred polyamides useful to form the sheath of the
bicomponent fibers of this invention are those which are
generically known by the term "nylon" and are long chain synthetic
polymers containing amide (--CO--NH--) linkages along the main
polymer chain. Suitable melt spinnable, fiber-forming polyamides
for the sheath of the sheath-core bicomponent fibers according to
this invention include those which are obtained by the
polymerization of a lactam or an amino acid, or those polymers
formed by the condensation of a diamine and a dicarboxylic acid.
Typical polyamides useful in the present invention include nylon 6,
nylon 6/6, nylon 6/9, nylon 6/10, nylon 6T, nylon 6/12, nylon 11,
nylon 12, nylon 4,6 and copolymers thereof or mixtures thereof.
Polyamides can also be copolymers of nylon 6 or nylon 6/6 and a
nylon salt obtained by reacting a dicarboxylic acid component such
as terephthalic acid, isophthalic acid, adipic acid or sebacic acid
with a diamine such as hexamethylene diamine, methaxylene diamine,
or 1,4-bisaminomethylcyclohexane. Preferred are
poly-.epsilon.-caprolactam (nylon 6) and polyhexamethylene
adipamide (nylon 6/6). Most preferred is nylon 6.
Importantly, the core of the sheath-core fibers according to this
invention is formed of a polymeric material which contains
relatively high levels of contaminants. Most preferably, the
contaminant-containing polymer forming the core of the sheath-core
fibers is compatible with the polyamide sheath. For example, if
uncontaminated nylon-6 is employed as the sheath polymer then
contaminate-containing nylon-6 is employed as the core polymer. The
amount of contaminant in the core polymer should be at least about
three times greater than any residual contaminants that may be
present in the sheath polymer.
The core will preferably represent about 50% or greater by weight
of the total bicomponent fiber weight according to this invention,
with the sheath representing about 50 wt. % or less. Surprisingly,
when the core is formed of contaminated nylon-6 and represents
about 80 wt. % of the bicomponent fiber, physical attributes
comparable to fibers formed of 100% nylon-6 are achieved.
The sheath-core fibers are spun using conventional fiber-forming
equipment. Thus, for example, separate melt flows of the sheath and
core polymers may be fed to a conventional sheath-core spinneret
pack such as those described in U.S. Pat. Nos. 5,162,074,
5,125,818, 5,344,297 and 5,445,884 (the entire content of each
patent being incorporated expressly hereinto by reference) where
the melt flows are combined to form extruded multi-lobal (e.g.,
tri-, tetra-, penta- or hexalobal) fibers having sheath and core
structures. Preferably, the fibers have a trilobal structure with a
modification ratio of at least about 2.0, more preferably between
2.2 and 4.0. In this regard, the term "modification ratio" means
the ratio R.sub.1 /R.sub.2, where R.sub.2 is the radius of the
largest circle that is wholly within a transverse cross-section of
the fiber, and R.sub.1 is the radius of the circle that
circumscribes the transverse cross-section.
The extruded fibers are quenched, for example with air, in order to
solidify the fibers. The fibers may then be treated with a finish
comprising a lubricating oil or mixture of oils and antistatic
agents. The thus formed fibers are then combined to form a yarn
bundle which is then wound on a suitable package.
In a subsequent step, the yarn is drawn and texturized to form a
bulked continuous fiber (BCF) yarn suitable for tufting into
carpets. A more preferred technique involves combining the extruded
or as-spun fibers into a yarn, then drawing, texturizing and
winding into a package all in a single step. This one-step method
of making BCF is generally known in the art as spin-draw-texturing
(SDT).
Nylon fibers for the purpose of carpet manufacturing have linear
densities in the range of about 3 to about 75 denier/filament (dpf)
(denier=weight in grams of a single fiber with a length of 9000
meters). A more preferred range for carpet fibers is from about 15
to 28 dpf.
The BCF yarns can go through various processing steps well known to
those skilled in the art. For example, to produce carpets for floor
covering applications, the BCF yarns are generally tufted into a
pliable primary backing. Primary backing materials are generally
selected from woven jute, woven polypropylene, cellulosic
nonwovens, and nonwovens of nylon, polyester and polypropylene. The
primary backing is then coated with a suitable latex material such
as a conventional styrene-butadiene (SB) latex, vinylidene chloride
polymer, or vinyl chloride-vinylidene chloride copolymers. It is
common practice to use fillers such as calcium carbonate to reduce
latex costs. The final step is to apply a secondary backing,
generally a woven jute or woven synthetic such as polypropylene.
Preferably, carpets for floor covering applications will include a
woven polypropylene primary backing, a conventional SB latex
formulation, and either a woven jute or woven polypropylene
secondary carpet backing. The SB latex can include calcium
carbonate filler and/or one or more the hydrate materials listed
above.
While the discussion above has emphasized the fibers of this
invention being formed into bulked continuous fibers for purposes
of making carpet fibers, the fibers of this invention can be
processed to form fibers for a variety of textile applications. In
this regard, the fibers can be crimped or otherwise texturized and
then chopped to form random lengths of staple fibers having
individual fiber lengths varying from about 11/2 to about 8
inches.
The fibers of this invention can be dyed or colored utilizing
conventional fiber-coloring techniques. For example, the fibers of
this invention may be subjected to an acid dye bath to achieve
desired fiber coloration. Alternatively, the nylon sheath may be
colored in the melt prior to fiber-formation (i.e., solution dyed)
using conventional pigments for such purpose.
A further understanding of this invention will be obtained from the
following non-limiting Examples which illustrate specific
embodiments thereof.
EXAMPLES
Physical properties for the samples in the Examples below were
obtained using the following test procedures:
Vetterman Drum Wear: The Vetterman Drum test simulated wear
according to ASTM D5417. The degree of wear exhibit by the samples
is determined by a visual rating relative to photographic standards
of wear from The Carpet and Rug Institute (CRI Reference Scale
available from CRI, P.O. Box 2048, Dalton, Ga., USA). Each of the
common types of carpet construction has a corresponding set of
photographic examples of unworn and worn samples. The wear levels
are from 5 to 1, where 5 represents no visible wear and 1
represents considerable wear.
Static Compression: The static compression was determined by
testing four samples from the material. Initial pile height of each
carpet sample was determined under a load of 0.5 psi using the
compressometer and methods as described above in determining Pile
Height Retention. The carpet was compressed for 24 hours under 50
psi. The compression force was then removed and the carpet vacuumed
and allowed to recover with no loading for another 24 hours,
following which the final reading was done. The result was the
average for the four samples reported as a percent of the original
pile height. Testing and measurements were conducted at 70.degree.
F. and 65% relative humidity.
Mass on Al Foil (Mass AF): The mass deposited on aluminum foil was
determined by dissolving deposits using methanol, after which there
was no residue remaining on the foil. The weight of the foil before
and after methanol extraction was determined with the mass of the
deposit in milligrams being determined by the difference between
such weight determinations.
Amount of Cyclic Oligomers: The amount of cyclic oligomers were
determined by HPLC techniques. Retention times were determined from
known standards. The percent (%) oligomers present was assumed to
be proportional to the area under the peak for each signal.
Estimates of mass were determined by multiplying the percent of the
component by the mass removed from the aluminum foil.
Example 1 (comparative)
Nylon-6 polymerized under a high dimer process was spun at
275.degree. C. through a 58 hole trilobal spinneret. The spin beam
was bicomponent and both extruders extruded the high dimer nylon-6.
The polymer ratios from the two extruders (as determined by the
polymer gear pump speed) produced a 20 wt. % sheath. The polymer
throughput per hole was 3.44 grams per minute (g/min). At the
spinneret, aluminum foil surrounded the fiber bundle. The amount
and relative composition of deposits on the aluminum foil are
reported in Table 1 below. This example gave some problems in
spinning, requiring several stoppages.
Example 2 (comparative)
Commercial spinning grade nylon 6 (BS 700-F from BASF Corporation
of Mt. Olive, N.J.) was spun at 275.degree. C. through a 58 hole
trilobal spinneret. The spin beam was bicomponent and both
extruders extruded the commercial spinning grade nylon-6. The
polymer ratios from the two extruders (as determined by the polymer
gear pump speeds) produced a 20 wt. % sheath. The polymer
throughput per hole was 3.44 grams per minute (g/min). The spinning
speed (speed of the first driven roll in the take-up process) was
500 meters per minute (M/min). At the spinneret, aluminum foil
surrounded the fiber bundle. The amount and relative composition of
deposits on the aluminum foil are reported in Table 1 below. This
example gave no problems in two hours of spinning.
Example 3 (invention)
A sheath-core bicomponent trilobal fiber was created using the
apparatus of examples 1 and 2. Nylon-6 polymerized from a high
dimer process formed the 80 wt. % by weight core and commercial
spinning grade nylon-6 (BS-700F from BASF Corporation of Mt. Olive,
N.J.) formed the 20 wt. % sheath. Both polymers were spun at
275.degree. C. through a 58 hole triobal spinneret. The spin beam
was bicomponent. The polymer ratios from the two extruders (as
determined by the polymer gear pump speed) produced a 20 wt. %
sheath. The polymer throughput per hole was 3.44 grams per minute.
The spinning speed (speed of the first driven roll in the take-up
process) was 500 meters per minute. At the spinneret, aluminum foil
surrounded the fiber bundle. The amount and relative composition of
deposits on the aluminum foil are reported in Table 1. This example
gave no problems in two hours of spinning.
TABLE 1 ______________________________________ Residues from
Examples 1-3 AF Capro CD Ex. Mass Mass Mass CT Mass No. (gm) %
Capro % CD % CT (gm) (gm) (gm)
______________________________________ 1 42.2 3 92 5 1.4 38.8 2.1 2
11.2 5 80 14 .6 9.0 1.6 3 20.0 NS 98 2 NS 19.5 0.5
______________________________________ Notes: AF Mass = Mass on
aluminum foil Capro = Caprolactam CD = cyclic dimer CT = cyclic
trimer NS = Not Sufficient signal to determine content
Example 4 (invention)
A sheath-core bicomponent trilobal fiber was created using the
apparatus of examples 1 and 2. Nylon-6 polymerized from a high
dimer process formed the 80 wt. % by weight core and commercial
spinning grade nylon-6 (BAS-700F from BASF Corporation of Mt.
Olive, New Jersey) through a 58 hole trilobal spinneret. The spin
beam was bicomponent. The polymer ratios from the two extruders (as
determined by the polymer gear pump speed) produced a 20 wt. %
sheath. The polymer throughput per hole was 3.44 grams per minute.
The spinning speed (speed of the first driven roll in the take-up
process) was 500 meters per minute. At the spinneret, aluminum foil
surrounded the fiber bundle. The amount and relative composition of
deposits on the aluminum foil are reported in Table 2. This example
gave no problems in 31/2 hours of spinning. The yarn was drawn to a
draw ratio of 3:1 and wound on a winder at a speed of approximately
1600 meters per minute. Spinning and drawing were done in one step.
This yarn was subsequently steam textured.
Two ends of this yarn were cabled and twisted to a nominal twist of
4.5 twists per inch. The cabled yarn was then autoclaved heatset
using a heating cycle of 265.degree. F.-240.degree. F.-265.degree.
F.-240.degree. F.-265.degree. F. The yarn was then tufted into a
1/8 gage cut pile carpet with 40 ozs. of face fiber per square yard
of carpet with a 1/2-inch pile height. Carpets were dyed to a light
brown shade and coated with latex. Vetterman drum and static
compression test results are reported in Table 2.
Example 5 (invention)
Example 4 was repeated, except that the nylon-6 with high dimer
content is in a 50 wt. % core and the sheath of commercial spinning
grade nylon-6 formed a 50 wt. % sheath. Spinning performance was
very good. Carpet testing results are reported in Table 2.
Example 6 (comparative)
Examples 4 and 5 were repeated, except that the fibers consisted of
100% high cyclic dimer content nylon-6. Spinning performance was
much poorer than that seen in Examples 4 and 5. Processing the
fiber into carpets was fine and the wear and compression properties
of the carpets is reported in Table 2.
Example 7 (Comparative)
Examples 4 and 5 were repeated, except that the fibers consisted of
100% commercial spinning grade nylon-6 BS-700F from BASF
Corporation of Mt. Olive, N.J.). Spinning performance was
equivalent to that seen in Examples 4 and 5. Processing the fiber
into carpets was fine and the wear and compression properties of
the carpets is reported in Table 2.
TABLE 2 ______________________________________ Carpet Performance
from Examples 4-7 Vetterman Drum Simulated Wear 5,000 Cycles 22,000
Cycles Static Visual Pile Height Visual Pile Height Compression
Grade Retention (%) Grade Retention (%) (%)
______________________________________ Ex. 4 3-4 88 1-2 81 95 Ex. 5
3 87 1-2 79 86 Ex. 6 3-4 91 2-3 79 87 Ex. 7 3-4 89 1-2 87 95
______________________________________
The data above demonstrate that bicomponent fibers according to
this invention will exhibit properties that are comparable to
fibers formed from 100% uncontaminated nylon-6.
Example 8 (invention)
Nylon 6 polymer (Ultramid.RTM. BS-700F nylon commercially available
from BASF Corporation) and a regenerated polymeric material
obtained from recycled nylon carpets having 90% nylon 6 and 10%
dirt and backing contaminants are used in this Example 8. The
materials are extruded using equipment as described in U.S. Pat.
No. 5,244,614. The relative amounts of each component are 75 wt. %
nylon 6 in the sheath and 25 wt. % recycled nylon 6 in the core.
Final extruder zone temperatures for each polymer are 275.degree.
C. for the nylon 6 and 275.degree. C. for the recycled nylon 6. The
spin pack temperature is 270.degree. C. The polymers are delivered
to a spin pack designed using thin plates such as described in U.S.
Pat. No. 5,458,972 (the entire content of which is incorporated
hereinto by reference), particularly FIG. 4 thereof so as to form a
trilobal bicomponent fiber having a concentric circular
cross-section core. The fiber is cooled, drawn and textured in a
continuous spin-draw apparatus (Rieter J0//10). The draw ratio is
2.8 and the winding speed is 2200 meters per minute.
Example 9 (invention)
Nylon 6 polymer (Ultramid.RTM. BS-700F nylon commercially available
from BASF Corporation) and a regenerated polymeric material
obtained from recycled nylon carpets having 90% nylon 6 and 10%
dirt and backing contaminants are used in this Example 9. The
materials are extruded using equipment as described in U.S. Pat.
No. 5,244,614. The relative amounts of each component are 70 wt. %
nylon 6 in the sheath and 30 wt. % recycled nylon 6 in the core.
Final extruder zone temperatures for each polymer are 275.degree.
C. for the nylon 6 and 275.degree. C. for the recycled nylon 6. The
spin pack temperature is 270.degree. C. The polymers are delivered
to a spin pack designed using thin plates such as described in U.S.
Pat. No. 5,458,972 so as to form a trilobal bicomponent fiber
having a concentric circular cross-section primary core and a
radially elongate, elliptically cross-section secondary core in
each of the trilobal fiber legs. The fiber is cooled, drawn and
textured in a continuous spin-draw apparatus (Rieter J0/10). The
draw ratio is 2.8 and the winding speed is 2200 meters per
minute.
Example 10 (invention)
It is known that recycled polymeric material will have some color
variation (typically a shade of gray-green) due to the different
colors and polymers between batches of recycled material. The
recycled polymer is thus measured for color difference against a
known color standard. Thereafter, a specified amount of carbon
black is added to the recycled polymer to correct the color to the
known standard color. The "color-leveled" recycled polymer could
then be spun as a core in the fibers according to Examples 8 and
9.
Example 11 (invention)
The core material of post consumer recovered nylon 6 was processed
using the techniques described in U.S. Pat. No. 5,535,945
(incorporated hereinto by reference) The starting materials were
colored, backed carpets of nylon 6 face yarn obtained from carpets
that had been worn and were being replaced. The carpet was ground
and much of the backing material is separated via a centrifuge and
a polymer filtration step. The resultant polymer material was
approximately 95% nylon 6. The remaining 5% was composed of latex
house dirt and possibly other contaminant components, as well as
polypropylene and residual colorants.
The recovered nylon 6 was melt spun in the core of a sheath-core
trilobal fiber. The sheath material was BS-700F (BASF Corporation,
Mount Olive, N.J.) with no additives. Polymer temperatures were
each 270.degree. C. The sheath was 75% of the fiber by weight while
the core was 25% of the fiber weight. The spinning apparatus was a
bicomponent spin head that utilized thin plates such as those
described in U.S. Pat. No. 5,344,297. A conventional one-step
bulked continuous fiber (BCF) carpet drawing-texturing, and winding
machine was used. Winding speed was approximately 2050 m/min.
Physical properties of these yarns measured according to ASTM D
2256-97 appear in Table 3 below. The yarn had a medium green
color.
Example 12 (invention)
Example 10 was repeated, except that approximately 1.60% of a green
pigment mixture was added to the BS-700F nylon-6 in the sheath
resulting in 1.2 percent pigment added to the total fiber. No
colorant was added to the core material. These fibers were a darker
green as compared to the fibers obtained in Example 10. Physical
properties of these yarns are summarized in Table 3 below.
Example 13 (comparative)
Example 12 was repeated, except that the core of the fibers was
bright uncolored BS-700F nylon-6. These fibers are a lighter shade
of green as compared to the fibers obtained in Examples 11 and 12.
Physical properties of the yarns are summarized in Table 3
below.
TABLE 3 ______________________________________ Physical Properties
of Fibers Linear Modi- Breaking Modulus @ Density fication Tenacity
Elongation 5% extension (denier) Ratio (g/denier) (% extension)
(g/denier) ______________________________________ Ex. 11 1253 2.76
2.61 17.1 7.50 Ex. 12 1241 2.74 2.72 35.6 6.80 Ex. 13 1211 2.76
3.01 38.6 8.16 ______________________________________
While the invention has been described in connection with what is
presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not to be
limited to the disclosed embodiment, but on the contrary, is
intended to cover various modifications and equivalents included
within the spirit and scope of the appended claims.
* * * * *